Diversity of non‐structural carbohydrates in grasses (Poaceae) from Brazil

Non‐structural carbohydrates (NSC) are the primary energy available for growth and dry‐mass production in forage grasses. They are also associated with tolerance to environmental stresses, including drought. Soluble carbohydrates, especially fructans of temperate forage grasses, have been extensively studied; however, little is known about NSC of tropical grasses. These plants are abundant in the Cerrado, a savanna‐like vegetation with a definite seasonality in rainfall distribution. Such an environment presents an ideal condition for the occurrence of fructans. However, the present analysis of carbohydrates in aerial parts of twenty‐four tropical grass species, mainly from the Panicoideae subfamily in the Cerrado, shows a distinctively different NSC profile when compared with temperate grasses. Free glucose and starch are common NSC found in most plant organs. However, free fructose and sucrose‐based oligosaccharides were only found in very low amounts. Sucrose was detected in higher amounts only in stems. A linear series of malto‐oligosaccharides was found in leaf blades, sheaths and stems of most of the Cerrado grasses, except for those from the Andropogoneae tribe. These results indicate a diversity of regulatory pathways of NSC metabolism in tropical forage grasses from the Cerrado.     

Habitat configuration for an obligate shallow‐water delphinid: The Indo‐Pacific humpback dolphin,Sousa chinensis,in the Beibu Gulf (Gulf of Tonkin)

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Year‐round natural spawning,early development,and the effects of temperature,salinity and prey density on captive ornate goby Istigobius ornatus (Rüppell, 1830) larval survival

Natural spawning, early development and larviculture of the ornate goby Istigobius ornatus in captivity were studied for the first time. I. ornatus spawned 46 times from 31 October 2013 to 31 October 2014. Fecundity ranged from 246 to 10,214 eggs per clutch, with an average hatching rate of 77.8% ± 9.9% (M ± SEM). Fertilized eggs (1.31–1.54 × 0.46–0.50 mm in diameter) were adhesive demersal and oval‐shaped. Embryonic development lasted 84 hr at 27.5 ± 0.5°C. Newly hatched larvae [2.12 ± 0.04 mm in total length (TL)] transformed to the juvenile stage completely when TL was 7.79 mm. Effects of different water temperatures (24, 28 and 32°C) and salinities (10, 15, 20, 25, 30, 35 and 40 g/L) on per cent survivals (%) and survival activity indices (SAIs) were tested. Survival was not significantly different under different temperatures; SAIs was significantly higher at 28°C. Larvae showed the significantly higher survival and SAIs at salinities 10–30 g/L than at 35 and 40 g/L. Effect of different prey densities on survival was significantly higher in 7 days post hatch larvae fed 20 and 30 rotifers/ml. These findings could guide future programs in captive breeding technology development and commercial production of other marine ornamental gobies.     

Effects of antimicrobial peptides on growth,morphology of foregut villi and related genes mRNA expression in the common carp (Cyprinus carpio)

A 60‐day feeding trial was conducted to examine the effects of different levels (0, 100, 200, 400 and 600 mg/kg) of antimicrobial peptides on growth, protease activity of foregut, the morphology of foregut villi and related genes mRNA expression level in the common carp (Cyprinus carpio). The results showed that the feed of antimicrobial peptides promote common carp growth, and the optimal dosage of antimicrobial peptides is 200–333 mg/kg in the common carp feed. The protease activity of 200 and 400 mg/kg groups were significantly higher than the control and other groups (p < 0.05). The foregut villus height with 100, 200 and 400 mg/kg antimicrobial peptide groups were significantly higher than control group (p < 0.05). The crypt depth of 200 and 400 mg/kg antimicrobial peptide groups were significantly lower than control group (p < 0.05). The ratio of villus height and crypt depth of 100, 200 and 400 mg/kg antimicrobial peptide groups were significantly higher than control group (p < 0.05). The ratio with 600 mg/kg group was significantly lower than the control group (p < 0.05). The IGF‐I gene expression level of 200 mg/kg and 400 mg/kg groups were significantly higher than the control group and 600 mg/kg group (p < 0.05). The IL‐1β gene expression level of 100 mg/kg and 200 mg/kg groups were significantly higher than the control group (p < 0.05). These results indicated up‐regulation of growth and immune related genes in antimicrobial peptides fed common carp. Correlation analysis showed that IGF‐I mRNA and IL‐1β mRNA were positively correlated with SGR. IL‐1β mRNA and FCR were significantly negative correlated. It indicated that growth and immune gene common regulated the growth of the carp under antimicrobial peptides intervention. In conclusion, antimicrobial peptides can improve growth and related genes mRNA expression in the common carp. Further studies using molecular biological technique or immunologic methods are required to conclude that antimicrobial peptides are beneficial in common carp.     

Effect of different ions on larval metamorphosis of the mussel Mytilus galloprovincialis

Metamorphic responses of pediveliger larvae of Mytilus galloprovincialis to different ions were investigated through a series of bioassays. Effects of tetraethylammonium chloride (TEA) on inductive effects of these above ions were also investigated. Excess ions including Li⁺, Cs⁺, Rb⁺ and Ca²⁺ induced larval metamorphosis at 10^?3 M to 5 × 10^?2 M in 24‐h exposure assays. In continuous exposure assays, only excess Ca²⁺ showed inductive activity and induced 25% metamorphosis at 5 × 10^?2 M. Larval responses to Li⁺ and Rb⁺were inhibited by TEA, while induction of metamorphosis by Cs⁺and Ca²⁺ was independent of the presence of TEA. Thus, these ions used can be useful inducers of larval metamorphosis for application in the aquaculture industry. The finding provides new insights on the biochemical mechanism controlling larval metamorphosis in this species.     

Physiological responses and HSP70 mRNA expression of GIFT strain of Nile tilapia (Oreochromis niloticus) under cold stress

An investigation on the physiological responses and HSP70 expression under cold stress was conducted on Genetically Improved Farmed Tilapia (GIFT) strain of Nile tilapia (Oreochromis niloticus). Tilapia were acclimated at 28°C as control and then the water temperature was reduced from 28°C to 15°C at a rate of 1°C h^?1, and serum biochemical indices, antioxidant enzymes and expression of HSP70 mRNA were analysed on days 0, 0.5, 1, 2, 3 and 5 after exposure to 15°C. The concentration of serum K, Na, Cl and Ca concentration showed instability during cold stress. Glucose rapidly increased on day 0 followed by a declining trend. Triglyceride, cholesterol, low density lipoprotein‐cholesterol signifi‐cantly decreased and high density lipoprotein‐cholesterol showed instability during cold stress. Aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase activities were prominently elevated under cold stress. Superoxide dismutase and catalase activities showed a remarkable rise on day 0.5 under cold stress, and gradually decreased thereafter. HSP70 mRNA level significantly increased both in liver and muscle under cold stress, especially on days 0.5 and 1. These results suggest that cold influences several physiological responses of tilapia, and the cold resistance and cold tolerance of tilapia will benefit from the enhancement of antioxidant enzymes activities and upregulated HSP70 mRNA expression.     

Genetic parameters for spawning and growth traits in the Pacific white shrimp (Penaeus (Litopenaeus) vannamei)

The aim of this study was to estimate genetic parameters for spawning traits and growth traits in a breeding line of Pacific white shrimp, Penaeus (Litopenaeus) vannamei, selected for growth and survival. Traits studied were number of eggs (NE) and number of nauplii (NN) and female body weight at insemination (FWI) and body weight at 130 days of age (BW130). Genetic parameters were estimated using a multivariate animal model. Heritability for NE and NN were estimated as 0.13 ± 0.04 and 0.03 ± 0.04 respectively. The contribution to NN total variation due to ‘factors associated with male’ effect was estimated as 0.47 ± 0.07. In the cases of FWI and BW130, heritability was estimated as 0.44 ± 0.08 and 0.19 ± 0.03 respectively. Genetic correlation between FWI and NE was estimated as 0.49 ± 0.15, between FWI and NN as 0.54 ± 0.39 and between NE and NN as 0.27 ± 0.41, whereas the genetic correlations of FWI, NE and NN with BW130 were 0.30 ± 0.13, ?0.21 ± 0.19 and ?0.25 ± 0.38 respectively. Although it is important to perform more studies on this issue, our results found no evidence of a genetic antagonistic effect between female reproductive traits and body weight at harvesting (130 days of age) in P. vannamei.